Functional Ecology This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/1365-2435.13669 This article is protected by copyright. All rights reserved Title: Climate change and defoliation interact to affect root length across northern temperate grasslands Authors: Zilong Ma 1* , Scott X. Chang 1 , Edward W. Bork 2 , Diego F. Steinaker 3 , Scott D. Wilson 3 , Shannon R. White 4 & James F. Cahill, Jr. 4 1 Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada T6G 2E3; 2 Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada, T6G 2P5; 3 Department of Biology, University of Regina, Regina, Saskatchewan, Canada, S4S 0A2; 4 Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9. (Present address of Shannon R. White: InnoTech Alberta, 250 Karl Clark Road, Edmonton, Alberta, Canada, T6N 1E4) * Correspondence author; Email: zilong@ualberta.ca, Phone: 807-355-5068 Acknowledgements We thank the Natural Science and Engineering Research Council of Canada (NSERC) for funding part of this research through a Strategic grant to JFC, EWB, SDW, and SXC and an NSERC Discovery grant to SXC. Author’s contributions JFC, SDW, EWB and SXC conceptualized and designed the study, SRW and DFS collected the original data; Z.M. performed the statistical analyses and wrote the first draft of the manuscript. EWB, SXC, and JFC revised subsequent versions of the manuscript. Conflict of interest: The authors declare no conflict of interest Accepted Article